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Filling Bolt Holes

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mrlewp87

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Last summer I removed the non-working power pole and pump from a 16 ft. skiff, knocking off about
20 lbs. from the stern. There had been hints from the seller and his son that the boat was heavy in the rear. Only today did I muster up the nerve to try and remove the large bracket that held the power-pole. Had no idea what I was going to find under the solid rectangular area of metal in contact with the exterior, but it was more needless extra weight in the stern. After removing it and finding it to be barely 5 pounds, I wished it had weighed more than it did, resulting in a greater load reduction. But good riddance, since it stuck out about 10" and just looked stupid!
There are 4 bolt holes that need to be filled, diameter of 7.5 mm, just shy of 5/16". Here's my recall of what I learned last summer regarding filling those holes. Drill the holes out with a bit that's one step (or so) larger than the holes. Thoroughly clean the insides of the holes and surrounding areas. Remove any rust, chipped surface material, old hardened glue, etc. Create a slight bevelled effect around each opening for the cement to fill, creating a sort of cap or head. Wipe all areas to be filled using acetone. Once dry, fill the holes. I've thought about how I'd keep the cement from running free and spilling out of the holes.
I'll be using SIX-10 "thickened" epoxy so no debate on that topic, thank you.
 
What is the hull material and the depth of the holes? Why not use a Stainless oval head machine screw for each?
 
Jim, please expand on that idea. I’d thought early on wether or not that something like that could be done, and reliable. In fact I wondered if I could use the same bolts in the holes but with some epoxy added?
Maybe l could’ve expanded on my* message to include these things; fiberglass hull, thickness of 1 to 1 1/4 inches. Most importantly 2 holes will always be under water, the other 2 holes- I certainly would hope NOT!, but will surely get wet a lot.
 
I was hoping to at least fill one of the upper holes to see how it goes. First time at this, and time wasn't on my side today. Then I thought better, and didn't want to spoil the mixer nozzle after doing just one fill. So I finished with the beveling at ends of each hole, all sanding and cleaning with acetone. So in the morning I hope to get all four holes filled, complete with a means of containing the epoxy within the holes. Attached is a photo of the holes and cleaned surface area. Oh, and another reason this boat is stern heavy- that "jack plate" at left in the photo. Not just the metal parts, but the resulting 5" further back in the placement of the engine shifts the balance for the whole boat more towards the back end.. . . . (( 3 tries to get the photo attached??))
 

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mrlewp87 said:
I was hoping to at least fill one of the upper holes to see how it goes. First time at this, and time wasn't on my side today. Then I thought better, and didn't want to spoil the mixer nozzle after doing just one fill. So I finished with the beveling at ends of each hole, all sanding and cleaning with acetone. So in the morning I hope to get all four holes filled, complete with a means of containing the epoxy within the holes. Attached is a photo of the holes and cleaned surface area. Oh, and another reason this boat is stern heavy- that "jack plate" at left in the photo. Not just the metal parts, but the resulting 5" further back in the placement of the engine shifts the balance for the whole boat more towards the back end.. . . . (( 3 tries to get the photo attached??))
Click to expand...

If you want to eliminate the holes and make them go away visually, you'll need to cover with gel coat or paint but they should be countersunk. Place tape over the the holes on the inside and poke a hole in it to create a bit of a dam, so the cement won't just flow out. Then, fill them until some of the cement oozes out. Fill the outside and place tape over the holes so the cement will stay in place. You can countersink after the first application. Watch some videos on YouTube- many good ones are available.

You won't want to leave the cement bare- gel coat repair kits are available from companies like Spectrum Color- you can give them your hull ID numbers and they can match the color. Thyse are available in small jars.
 
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